Rope actuated starter gearing for internal combustion engines



J1me 1961 c. A. MENDENHALL ETAL ROPE ACTUATED STARTER GEARING FORINTERNAL COMBUSTION ENGINES Filed July 31, 1959 @UUGIQS Y INVENTORS ,2?A7; I A TORNEY Unite The present invention relates to rope actuatedstarter gearing for internal combustion engines, and more partic ularlyto gearing of the automatically engaging and disengaging type.

It is an object of the present invention to provide a novel gearingdevice of this type which is efiicient and reliablein operation Whilebeing simple and economical in construction.

It is another object to provide such a device which engages promptlyupon initial actuation of the rope drum and disengages freely when theengine starts, with no tendency after disengagement for the drive pinionto rebound towards the engine gear.

It is another object to provide such a device which maintains itsengagement with the engine gear throughout the tractive actuation of therope irrespective of the initial or irregular explosions of the engine.

It is another object to provide such a drive including means forrewinding the rope on the drum after each actuation thereof and novelmeans for adjusting the tension of the rewinding means.

Further objects and advantages will be apparent from the followingdescription taken in connection with the accompanying drawing in which:

FIG. 1 is a side elevation, partly broken away and in section, of apreferred embodiment of the invention;

FIG. 2 is a sectional detail taken substantially on the plane of line2-2 of FIG. 1;

FIG. 3 is a side elevation, partly broken away, of the rewind springtension adjusting rod and clutch member;

FIG. 4 is an exploded detail perspective of the sleeve, rewind springclutch member, tubular housing member and the robe drum; and

FIG. 5 is a reduced sectional detail of an expander member for use in amodified version of the preferred embodiment. x In FIG. 1 of the drawingthere is illustrated a casing 11 supporting and housing a manual ropeactuated starting assembly generally indicated at 12 and a starter driveassembly generally indicated at 13.

The starter drive assembly 13 is supported on a sleeve 14 having abearing and clutch member 15 formed integrally therewith. Said bearingand clutch member is rotatably and slidably supported in a bushing 16provided in a wall portion of the casing 11. The sleeve 14 has a smoothportion 17 upon which a screw shaft 18 is rotatably and slidablyjournalled. The bearing and clutch member 15 of the sleeve 14 has aradial shoulder 21 formed with dentils 22 which engage and cooperatewith dentils 23 formed in the end of the screw shaft 18 therebymaking-the screw shaft a driven coupling member and in concert with thebearing and clutch member 15 providing an overrunning driving coupling.The screw shaft is axially biased by a spring washer 24 journalled onthe sleeve 14 and interposed between a pinion thrust washer 26 and anend washer 27, whereby the dentils 23 are yieldably maintained inengagement with the dentils 22. A stop nut 28 secured to the threadedextremity 29 on the sleeve 14, as an incidental function, retains thespring 24 and washers 26 and 27 in their proper axial relationship.

A pinion assembly 30 is threaded on the screw shaft 18 and duringstarter operation, hereinafter described, is longitudinally traversed onthe screw shaft 18, causing.

rates Patent 2,987,059 I Patented June 6, 1961 2 the pinion 31 to meshwith a gear 32 of the engine to be started. Within the pinion assembly30 is a spring actuated detent member 33 which bears upon the threads ofthe screw shaft and in the pinion-meshed condition engages a lockingpocket 34 in said screw shaft, locking the pinion assembly in mesh untilthe engine causes the pinion to rotate beyond a predetermined rate. Adust cover 36 is fixedly secured to the pinion assembly to effectivelyshield the starter drive assembly from the ingress of foreign anddeleterious substances.

To insure that the pinion assembly 30 vw'll longitudinally traverse thescrew shaft a retarder spring 37 is seated in a circumferential groove38 formed in the pinion frictionally bearing therein. A free end of thespring 37 is outturned, as at 39, a suflicient amount to allow it toengage in an axial recess 41 formed in the casing 11 thereby effectivelylimiting the rotational displacement of the spring while allowing thespring and the associated pinion assembly relatively unrestrainedlongitudinal movement.

The manual rope actuated starting assembly 12 includes a rewind springtubular housing member 42 which is rotatably supported at one extremityby an appropriate bearing means formed in the casing 11, as at 43, andat its opposite extremity is fixedly coupled to the knurled extension 44provided on the bearing and clutch member 15. Relative rotation betweenthe tubular housing 42 and the member 15 is prevented by fixedly securedthese components together as by brazing.

A drum 46 is mounted on the external surface of the tubular housing 42and connected for rotation therewith by means of radial tongues 47projecting outwardly from said tubular housing and engaging cooperatingslots 48 formed in said drum. Longitudinal displacement of the starterdrive assembly 13 away from the engine gear is resisted by amesh-enforcing spring 49 wound or Wrapped about the external surface ofthe tubular housing 42 compressively engaging both the drum 46 and athrust washer 50 seated against the bearing 43 of casing 11.

Movement of the starting assembly 12 in the meshing direction towardsthe engine gear is limited by a radial shoulder 53 of the drum 46abutting the casing bushing support 54.

The drum 46 is formed so as to receive a starter rope 52 which is coiledon the drum and anchored thereto as shown at 51, thus providing themeans to tractively actuate the drum and starting assembly in the normalmanner.

A multi-coi1 rewind spring 56 is contained in the tubular housing 42with the spring extremity adjacent the casing 11 being formed with aninturned leg 57 anchored to the casing in any convenient manner, as at58. The opposite extremity of the rewind spring 56 is wrapped about apin-like member 59 of a spring rewind clutch member 61. The clutchmember 61 rotatably and slidably fits within the tubular housing 42 andhas a short guiding boss 62 upon which a portion of the rewind spring isseated. Extending from said clutch member are diametrically opposed lugs63 which disengageably coact with slots 64 formed in the extremity ofthe knurled portion 44 of the bearing and clutch member 15. An adjustingrod 65 coaxially aligned with the tubular housing 42 and the sleeve 14extends from the clutch member 61 and is slidably and rotatablyjournalled in the bore 66 of the sleeve 14 to project beyond the starterdrive cover 36. A compression spring 67 is retained on the end of theadjusting rod 65 by suitable means such as a split thrust washer 68 andbears against the stop nut 28 on the sleeve 14.

The spring 67 thus exerts an axial force on the clutch member 61normally keeping the lugs 63 interengaged; with the slots 64 in thebearing and clutch member 15,

and incidentally, overcoming a reasonable amount of opposing biasexerted by the rewind spring 56. A kerf 71 is provided in the end of theadjusting rod 65 to receive a screw driver or the like for adjustment ofthe rewind spring tension.

A tube or rod 72 confined within the rewind spring 56 is-- provided toassure the proper alignment of the spring 56 and to eifectively preventthe rewind spring 56 from winding upon itself when initial torsionalenergy is imparted thereto. The rod 72 preferably loosely fits withinthe springs inner diametnc dimensions, but lengthwise it issubstantially shorter than the rewind spring to provide the necessaryspace or clearance for the longitudinal movement of the clutch member 61during the disengagement of the lugs 63 and the slotted extremity ofbearing and clutch member 15.

In Fig. 5 there is illustrated a modified expandable tube 73 forreplacing the tube member 72. The expandable tube 73 comprises a pair oftelescoping closed tubes 74 and 76 and confined within said tubes is acompression coil spring 77. The spring 77 yieldingly urges the tubemembers 74 and 76 into abutting engagement with the. adjacent portionsof the casing 11 and the clutch member 61 thus maintaining the clutchmember 61 and bearing and clutch member 15 in their engaged, butdisengageable, condition. Utilization of the expandable tube 73 willeliminate the need for the compression spring 67 and the associatedwasher 68 since the bias exerted by the tube on the clutch will causethe adjusting rod to operably protrude freely beyond the dust cover 36.

In operation, the adjusting rod 65 is depressed against the forceexerted by the spring 67 or the expandable tube 73 by a suitable toolsuch as a screw driver so thatthe clutch member 61 is disengaged fromthe bearing and clutch member 15. Rotation of the adjusting rod 65 bysaid tool, will cause the rewind spring 56 to be wound up and assume adesired degree of torsional tension. Release of the depressive force onthe adjusting rod when the, lugs 63 and slots 64 are in registry willallow the clutch member 61 and the bearing and clutch member 15 to againassume a unitary driving relationship. Any tendency for the startingassembly to unwind or unleash the torsional energy stored in the rewindspring 56 will be restrained by the engagement of the starter ropehandle (not shown) abutting the casing 11.

To start the engine the actuator rope 52 is rapidly withdrawn from thedrum 46 causing the drum to rotate at an appreciable rate of speed.Rotation of the drum is transferred to the tubular housing 42 and thedriving clutch member 15 by means of the tongue and slot en gagements 47and 48, respectively. Rotation of the drum has a two-fold effect:

(1) Increasing torsional energy stored in the rewind spring '56;

(2) Rotating the screw shaft 18 through the dentil' over-running drivingcoupling, which in turn will cause the rotationally retarded pinionassembly 30 to longitudinally traverse the screw shaft and mesh thepinion 31 with the engine gear 32. Longitudinal traverse of the pinionassembly after complete meshing engagement is limited by the stop nut 28and thereafter the rotational energy of the screw shaft is transferredto the pinion and thence to the engine to be started. The screw jackaction between the pinion and screw shaft forces the screw shaft backagainst the dentils 22 of the bearing and clutch. member 15, thusinsuring against premature disengagement of the overrunning drivingcoupling.

In the meshed position the pinion detent 33 will drop into the lockingpocket 34 and maintain the pinion in the engaged condition until theengine has started and attained a predetermined speed. When the enginehas attained the predetermined speed, the detent 33 is Withdrawnbycentrifugal force. Of course, whenever the speed of the pinion attains aspeed greater than the diminishing speed of the starting assembly thedriving coupling formed by dentils 22 and 23 will be caused to beoverrun, and thus effectively disconnect the starter drive assembly 13from the starting-assembly 12.

The release of the tension on the actuator rope 52. by the operator willallow the rewind spring 56 to release its stored torsional energywhereby the manual starting assembly 12 is revolved in a reversedirection to its initial position causing the actuator rope 52 to beproperly rewound on the drum 46.

It can be appreciated that the initial storage of torsional energy inthe rewind spring is most desirable and is necessary to supplement thetorsional energy imparted to the spring during actuation therebyinsuring proper and complete operation of the rewind structure duringweak or partial starts.

Although but one form of the invention has been shown and described indetail, it will be understood that. changes may be made in the designand arrangement of the parts without departing from the spirit of theinvention.

We claim:

1. In a manually operable starting device for internal combustionengines a casing, a tubular member rotatably mounted therein, a drivingdrum mounted on the tubular member and connected thereto for rotation inunison, a hollow sleeve fixedly united to the tubular member, ascrewshaft slidably journalled on said sleeve, an overrunning drivingconnection from the sleeve to the screw shaft, a pinion threaded on thescrew shaft for movement into and out of mesh with a gear of an engineto be started, an abutment on said sleeve limiting the meshing movementof the pinion, means including the driving drum for rotating saidtubular member from its initial position to cause the pinion to engageand rotate the engine gear, and yielding means operatively engaging saidtubular member for rotating it backwards to its initial position.

2. A starting device as set forth in claim 1 including further, meansincluding a rod slidably journaled in said sleeve for engaging andadjusting the tension of said yielding means.

3. A device as set forth in claim 1 in which the tubular member andhollow sleeve are axially slidable in. the casing, abutment meanslimiting axial movement thereof in the direction to mesh said pinionwith the engine gear, and. yielding means urging said tubular member andsleeve toward said abutment means.

4. A device as set forth in claim 2. including further a clutch andbearing member journalled in said casing uniting thetubular member andhollow sleeve, said yielding means for rotating the tubular memberbackward. including a torsion spring therein anchored at one end of thecasing, and said adjusting means including a clutch member having thefree end of said torsion spring attached thereto, the clutch memberbeing rotatably and slidably mounted in said tubular member and having adisengageable connection with said clutch and bearing member.

5. A device as set forth in claim 4 in which said clutch member isrigidly mounted on said tension adjustingrod for rotation therewith, andfor axial movement thereby into and out of clutching engagement withsaid clutch and bearing member; and further comprising means exerting abiasing force upon said clutch member yieldingly. urging said clutchmember into engagement with said clutch and bearing member.

6. In the device set forth in claim 5, the biasing means comprising apair of opposed telescoping tubular elements confined within saidyielding means, and a spring member compressively confined within thetelescoping tubular elements whereby the tubular elements are biasedinto engagement with the casing and clutch member to maintain theengagement of the disengageable clutch connection.

7. A device as set forth in claim 1, including further a bearing andclutch member uniting the tubular meme ber and the hollow sleeve, saidbearing and clutch member having a dentil overrunning couplingengagement with said screw shaft and, thereby limiting the travel of:the; screw shaft'on said sleeve away from the engine gear, and

5 & yielding means urging the screw shaft toward the clutch ized bymeans within the tubular member for maintaining and bearing. the properalignment of said yielding means.

8. A device as set forth in claim 7, including further centrifugallyreleased detent means for resisting demesh- References cued m the fileof thls patent ing movement of the pinion on the screw shaft until the 5UNITED STATES PATENTS pinion has reached a predetermined rotationalspeed. 2,385,963 Beard Oct. 2, 1945 9. A device as set forth in claim 1,further character- 2,847,985 Strang Aug. 19, 1958

